How To - Choose Tires

Tire choice depends on how you intend to drive and enjoy your Mustang

Jim Smart

November 9, 2011

We expect a lot from our tires. We want them to look good and handle well. And we also want them to last. To get that, we need all of the elements in place-the right tire for the job, tire quality, solid chassis component integrity, correct wheel offset, and proper front-end alignment and tracking. We also want the tires to clear wheelhouses and fender lips under all conditions, including those times when we have a rotund buddy in the back seat. Shopping for tires for Mustangs, including classic and Fox-body, is different from shopping for skins for the family car.

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White sidewall radial tires for classic Mustangs, for example, are not as plentiful as they once were because mainstream demand for whitewalls has fallen off in recent years. How many new cars do you see today with white sidewall tires? If you're in the market for white sidewall radial for your classic Mustang, it becomes more challenging because you likely won't find them on the shelf at your local tire store. However, most tire stores can order a set for you depending on their distribution sources.

Tires perform a complex job even under the simplest of circumstances. They have to transfer the engine's power to the pavement to get you moving, which involves a lot of stress. They have to absorb road shock and go with the unknowns of the average stretch of highway. The sidewalls absorb road shock and flexes from side to side as we steer. Sidewall height affects ride quality and handling characteristics. A tall sidewall gives us a better ride, but sloppy handling. A shorter sidewall, like we see on new cars today, reduces ride quality yet makes handling more crisp.

Tire choice gets tricky when building a restomod because options become more numerous. There are different wheel sizes, offsets, widths, tire profiles, tread patterns, rubber hardness, and more to consider. What do you want a tire to do for your restomod? First, we think about looks. Second, we think about what we want the tire to do in terms of handling and ride quality. Rubber composition gets really involved and can boil down to as many as 25 different types and hardnesses. The harder the rubber, the longer it generally lasts. However, the harder it is, the rougher the ride.

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Tire sidewalls contain valuable information that is useful to your tire buying efforts. Today, you will see either a "P" for Passenger Car or "LT" for Light Truck. The biggest mistake we see out there, aside from under inflation, is incorrect tire size. This is an error committed more by tire stores than customers because it can be challenging to compare original 695x14 tires to a comparable metric radial tire. Here's how a typical P-metric radial tire size stacks up:

P205/70R15

P = Passenger Car

205 = Tread Width in Millimeters

70 = Aspect Ratio (Tire Height is 70 percent of its width)

R = Design Type (Radial)

15 = Rim Diameter in Inches

You will also see other characters, such as "63," which is the tire's load rating. Then "H," which is the tire's speed rating. Then something like "M&S," an all-season rating or the tire's intended use. A speed rating is little more than the tire's capacity for heat. The quickest way to tire failure is heat, which is why this rating is so important. If you're going canyon cutting or open highway at high speed, heat becomes a huge factor because excessive heat quickly breaks down the rubber compound.

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Tire selection boils down to how you drive, driving conditions and frequency, ride quality, and appearance. If you live in a rainy climate, you want a good all-season tire designed to manage water. Bias-belted and bias-ply tires are cosmetic only and should be used only for occasional drivers and trailered show cars. Most of our readers are going to be interested in some form of radial tire for their occasional or daily driver.

You have two basic choices on radial tires for classic Mustangs-white sidewall and raised white letter. The BFGoodrich Radial T/A remains the standard for performance Mustang applications. We still buy them in great numbers. Tire Rack also has the Kumho Solus KR21 white sidewall radial for roughly $67 each for 195/75R/14, which is an excellent value.

Aspect Ratio

In the 1960s, we heard the terms "70 Series" or "60 Series" as they related to tire size, such as F70x14, not always knowing what they meant. We did, however, understand that the lower the series number, the wider the tire. In the old days, if you had 60 Series tires (for example G60 x 15), you had wide tires typically located in the rear wheelwells for good traction. However, some factory performance Mustangs, like the Boss cars, were equipped with 60 series tires at all four corners for good contact patch in the turns. This number is known as aspect ratio, a measure of tire height to tire width in percentage.

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The aspect ratio is measured from the bead to the tread versus tread width. If we're dealing with a 70 series tire, for example, tire height is 70 percent of its width. As this number goes lower, the tire gets wider compared to height. High aspect ratio tires are more old-school with plenty of sidewall to absorb road shock. As the aspect ratio goes lower, we have less sidewall, wider tread, and better handling. However, they sacrifice ride quality. Wider tires with less sidewall offer improved lateral stability and help keep a good contact patch. This enables our Mustangs to hold the road better. By the same token, if we reduce tread width and increase sidewall height, handling suffers but ride quality improves.

Coker Tire tells us how important sidewall design is to a Mustang's appearance. This approach began with white sidewalls early on, then moved to dual narrow band whitewalls. Somewhere in all of this excitement, automakers started fitting cars with sidewalls in red, gold, and blue. Corvettes, for example, were fitted with gold bands. Shelby liked the narrow blue band sidewalls on its Goodyear Speedway tires. Coker offers all three sidewall colors on both bias-belted and radial performance tires, including BFGoodrich and U.S. Royal in bias-ply and Coker Classic and BFGoodrich in radials.

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While Coker tends to be known for Firestone, BFGoodrich, and U.S. Royal, Kelsey Tire is recognized for Goodyear reproductions such as the Speedway and Polyglas for Shelbys and other high-performance Mustangs. Kelsey also has popular Goodyear bias-ply tires, like the Power Cushion, for vintage Mustangs.

To the best of our knowledge, the Goodyear Gatorback, which was original equipment on 1980s Fox-body Mustangs, isn't being reproduced at press time. However, there are suitable performance tires still available from Goodyear for these late-model classics. The Goodyear Eagle GT All-Season performance tire is a good replacement for Gatorbacks until a good reproduction comes along.

Another popular standby for Fox-body Mustangs is the Firehawk Wide Oval, which comes in a variety of styles, aspect ratios, and tread patterns. Firestone's website (www.firestonetire.com) has a user-friendly approach where it stacks selection up with an easy-to-follow format of both Firestone and Bridgestone performance tires. Firestone starts out with the traditional Firehawk Wide Oval as a good baseline tire and leads you through the entire line-up of Wide Ovals. Your job is to check out the Firehawk menu and determine which Firestone is best for your early or Fox Mustang.

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You can't rule out BFGoodrich in your Mustang tire search. For the classics, the ageless and legendary Radial T/A with tasteful raised white letters is perfect for cars that once had Goodyear Polyglas GTs or Firestone Wide Ovals. First introduced in the 1970s, the Radial T/A was North America's first high-performance radial tire. It offers great longevity and handling. BFGoodrich remains true to the Radial T/A reputation for being the perfect high-performance Mustang street tire because it fits so well and looks so darned good. If ever a tire had sex appeal, it's the Radial T/A.

If you want to kick it up a notch, there's the BFGoodrich g-Force series radial tire for more aggressive driving. We're thinking of the g-Force Super Sport A/S or the Sport, both excellent street tires with a sticky contact patch. The Super Sport A/S offers the best longevity of the two. It is always a tradeoff because if you want high mileage, forget the sticky contact patch because you're dealing with a harder compound. Softer, stickier, better handling tires don't last as long.